Combination drier



Oct- 6, 1925. 1,556,096

a T. A. GARROW COIBiNATION DRIER 1 6 14? 725000; am ox.

Filed March 11, 1924 Away/57's.

Patented Get. 6, 11925..

- UNITED. STATES THEODORE A. GARROW, OF LOS ANGELES, CALIFORNIA.

COMBINATION DRIER.

Application filed March 11, 1924. Serial No. 698,531.

To all whom it may concern:

Be it known that I, THEODORE A. GARRow, a citizen of the United States, residing at Los Angeles, in the county of Los Angeles, State of California, have invented a new and useful Combination Drier, of which the following is a specification.

This invention relates to equipment for drying granular materials such as sand, gravel and clays.

An important use of a device of this character is in the preparation of paving materials. A widely used and highly satisfactory paving material employs in its composition sand, clay, asphaltum and possibly gravel. In combining the granular materials with the asphaltum, it is quite essential that they be in perfectly dry state and for the purpose of drying these materials Which may have previously been washed, large rotary drying machines are employed. Such machines generally consist of a tubular shell mounted substantially horizontally so that it ill rot-ate on the axis thereof. Into the forward end of this shell the materials to be dried aredelivered and hot gases are at the same time directed into the rearward end of the shell, these gases belng brought into contact with the material as they churn within the shell and advance thercalong toward the rearward end of the shell. A drier of this type is particularly suited to the dryin of sand and gravel and operates very efficiently with such materials. The equipment, however, is not found entirely satisfactory for the drying of clays which, on becoming dried, form a very light dust which is very susceptible to being carried off by the blast of heated air as it travels from the shell.

I have found that by introducing the heated air at the forward end of the shell so that the direction of flow thereof will be the same as the movement of material through the drier, a very efficient drying action may be accomplished without the carrying off of large quantities of finely powdered clay through the exhaust system. In the standard form of equipment, the agitation of materials is greatest at the forward end of the drier, and it is at this point that the drying gases leave the drying chamber, thus carrying off damp clay dust from the forward end of the drier. In my device,

the clay is carried through the drier and that which is carried off with the air blast is perfectly dry and may be separated centrifugally or otherwise and used in the manufacture of paving material; whereas materials now carried off in the blast contain too much moisture to be usable in combination with hot asphalt.

The especialadvantages and further objects of the invention will be made evident hereinafter. Y

Referring to the drawing which is for illustrative purposes only,

Fig. 1 is a partly sectional diagrammatic view of a drier embodying the features of my invention. 7

Fig. 2 is a section taken substantially upon a plane represented by the line 22 of Fig. 1.

As shown in the drawing, the invention employs a cylindrical shell 11 which is mounted upon bearings 12 and rotated through a gear 13 by driving means, not shown. The interior of the shell is equipped with vanes 15 which serve to pick up .materialsplaced in the shell, as ,it rotates so that these materials will fall back through the space within the shell, which space is generally maintained at a high temperature by the introduction of hot gases thereinto. For the purpose of heating the interior of the shell 11, my invention employs a combustion chamber 17 equipped with a burner 18 situated at the forward end of the shell; and a combustion chamber 19 situated at the rearward end of the shell and having therein a burner 20, these combustion chambers having air valves 32. In the drawing, the combustion chambers are indicated in simple shell form but may be lined with brick or other refractory material as the occasion may demand. At the forward end of the shell is a housing 22 equipped with a charging opening 23 which leads to a chute 24, the lower end of which chute rests adjacent to the inner end of the combustion chamber 17 and slopes inwardly. so as to deliver the material to be dried into the forward end of the shell 11. At the rearward end of the shell is placed a discharge housing 81 in which the combustion chamber 19 is mounted and'which is'equipped with an upwardly extending cap member 25 having a lateral outlet 26 which joins with a longitudinal pipe 27., This pipe 27 eX- tends to the lateral outlet- 28 of a cap memher 29, mounted on the forward housing 22,

from which there upwardly extends a stack; 30.

The drier shell 1 1 is arranged to be mounted at a slope downward from the forward end thereof to the rearward end so asto .pro: duce a movement of the materials being dried toward the dischargeend of the shell. When rock, gravel or sand is being dried, the materials; are fed into the shell through the charging opening 23 and a blast of heated combustion gases are directedby the burner 20 into the shell, thus producing a flow ofheated gases, in counter direction tothatof the materials being, dried. here the, drying operation is carried on in a. slow rate of speed, and where the materialsbeing dried are. quite-heavy and contain but little; dust, the valves 35 and 48 may be opened and. the. valvesv 86, 37, and 38 shut, so that thespent gases may be drawn from the forward end of the shell'by the draught produced inthe stack 30. If a rapid drying. action is desired, and where there is considerable dust carried off-by; the blast, a very strong blast of; airmay be produced within the shell by closing the valve 48 opening valves 35, 86 and 37, and using a blower..t0, the airufrom the blower-being directed through. dust collec-.. ors;

When; h a pa a u is be n p oy for; finely powdered; materials such as clays, thecqmbustion,chamber, 1f? and-the burner 7 18 are; used, thus introducing. hot gases into the forward. end of j the shell as indicated at 42, these gases traveling from thefront to the rear. ofthe shelhwhile the material be ing, dried advances in thesame direction. It willbe; recognized, that the materials at the forward; endof: the, shell are brought into contact witlrthe gases when these gases are at theirhighest temperature .and a grad;- ual coo-ling of the. gases take. place as; they travel rearwardly inLth-e shell and produce a drying action on the clayv therein. The d y g-g ses re Pr e a y qa r edi r m the .shellthrough the cap ,membenize by operation of: the exhaust blower-40. Whfineither burner isofi', its valve 32=is shut.

Where the materials being, dried, are exceedingly. light, the, quantity picked up and carried off bythe blast be quite large. This quantity, however, is thoroughly dried, having passed entirely through the drier, and may beseparatedfrom theair. blast; by centrifugal separators, or other. means, and,oon.- veyedto theasphalt mixers. In this manner, the entire production of, the drier is utilized, therebeing no losses, as in the present pro.- cessof drying fine materials.

I claim as my invention:

1'. In a, device of; the character described, the combination of: a rotary tubular shell; meansat the. forward end of said shell; for delivering a material thereinto; means at deliveringv a material. thereinto; means at.

the rearward end of saidshell throughwhich said material is discharged; and means equipping, said-shell for use. in dryingthght or heavy materials, consisting, of burners situated at each endv oflsaid shelllforselee ly pro ng aflow-biase lir slasa d:

shell from either end thereof 3-111 a device of they charactendescribed,

the combinationof: a rotary-tubularshells means at the forward end of; said shellfor deliveringv a material thereinto; means at;

the rearward; end of said shelllhrough which said material is discharged, means equipping, said shell for use in drying. light; or heavy} materials, consisting of means for selectively.

producing a flow of gasesthrough asidshell from either-endthereof and exhaust means at each end of said shell; for drawing olfgases fromthe interior: of said shell.

l. Ina deviceof the characterdescribed, the, combination of: a rotary-tubu lar shell means, at the forward end of said shell-for delivering a material thereinto; means at the rearward end; of said; shell through which said material is discharged; and means equipping said shell for-usein drying light'or heavy materials, consisting of hous ings forming combustion chambers at each end; of said" shell, and burners situated in each of said housings.- for; selectively produce ing a fi ow-ofg asesthrough said. shell from either end-thereof:

5. In a device of: the character described, the combination of:v a. rotary tubular shell; means at the forward: endof said: shell for delivering a material thereinto; means at the rearward end of saidshellthrough which said material is discharged and.- means equipping said; shell for usegin drying. light materials, consisting of means for. introduce ing hot'gases into the forward endyof said 8116111; and exhaust means for drawing, off said gases from therearward end; ofsaid shell.

6; In a device, of the character described, the combination of: arotary tubular-shell; means at the forward. end of, said shell for delivering a. ,material thereinto; means at the rearward end of said. shell through which said material is discharged; and means equipping said shell for use in. dryingilight materials, consisting of; means for introducing hot gases into the forward end Of S id shell; and exhaust means for drawing off said gases from the rearward end of said shell.

7. In a device of the character described, the combination of: a rotary tubular shell; means at the forward end of said shell for delivering a material thereinto; means at the rearward end of said shell through which said material is discharged; means equipping said shell for use in drying light or heavy materials, consisting of means for introducing hot gases at each end of said shell; a draw off housing at each end of said shell; a pipe connecting between said housings; exhaust means at one end of said pipe; and means controlling the flow of gases through said pipe.

8. In a device of the character described,

the combination of: a rotary tubular shell; means at the forward end of said shell for delivering a material thereinto; means at the rearward end of said shell through which said material is discharged; means equipping said shell for use in drying light or heavy materials, consisting of means for selectively producing a flow of gases through said shell from either end thereof; a draw off housing at each end of said shell; a pipe connecting between said housings; exhaust means at one end of said pipe; and means controlling the flow of gases through said plpe.

In testimony whereof, I have hereunto set my hand at Los Angeles, California, this 21st day of February, 1923.

THEODORE A. GARROW. 

